Fasteners, such as nails, staples, brads, and pins, that are to be subjected to exterior or weathering applications are typically made from wire that has been plated, or galvanized, usually with zinc. Aluminum has sometimes been introduced in the plating process with zinc for enhanced corrosion performance as well.
The plating step is typically either electrolytic or via a molten zinc, or zinc and aluminum bath or pot. The latter is characterized as a “hot dipping” process.
The steel used for the fastener may be composed of various chemistries and demonstrate significant property differences depending upon the degree of cold working through conventional wire drawing practices, differences in the basic steel constituents, and whether or not a stress relieving (patenting or annealing) process stage has been introduced.
Such plated fasteners are commonly used with pressure treated wood. Pressure treating is used to prevent decay and insect damage to wood used for playground equipment, decks, landscaping ties, and fence posts. Copper chromated arsenate (CCA) has been a common preservation treatment for wood. As CCA includes arsenic, alternatives to CCA, such as alkaline copper quatenary (ACQ), are presently available. The chemical treatment of pressure treated wood, such as ACQ wood, can react with metal fasteners to corrode the fasteners.
Fast-acting fastener driving tools are commonplace in the building industry. Fasteners, such as nails, are assembled in strips that are adapted for use in a magazine of such tools. The strips are flat, the nails or other fasteners are parallel, and the fasteners are maintained in position using a collating component, typically including an adhesive and a backing material, to bind the nails or other fasteners together in a parallel arrangement, to provide a collated strip of fasteners for use in fastener driving tools.
In order to improve the weathering resistance of fastener assemblies for use with fastener driving tools, particularly when used with treated wood products, there is a need or desire for a coating which has the ability to provide improved corrosion resistance. There is also a need for improved methods for applying such coatings to fasteners, and particularly fastener assemblies for use with fastener driving tools.